(function (doc, win) {
    var docEl = doc.documentElement, resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
    recalc = function () {
      var clientWidth = docEl.clientWidth
      if (!clientWidth) return
      docEl.style.fontSize = 16 * (clientWidth / 375) + 'px'
      console.log(docEl.style.fontSize) 
    }
    if (!doc.addEventListener) return
    win.addEventListener(resizeEvt, recalc, false)
    doc.addEventListener('DOMContentLoaded', recalc, false)
  })(document, window)